Quick-connect couplers heretofore have been used to interconnect with a mating nipple for transfer of a pressure fluid therebetween. Many of these quick-connect couplers have included valves for controlling fluid flow through the coupler. In some of these valved couplers, internal valve components are automatically operated by interconnection with the mating nozzle.
Various types of valves have been used with prior art couplers including flow control ball valves that are rotatable through 90.degree. between fully open and closed positions. Also known are interlock devices that are intended to permit coupling or decoupling of the coupler and mating nozzle only when the valve is closed. Some prior art couplers are known to have provision for venting the coupler to atmospheric pressure prior to coupling and uncoupling.
A need exists for an improved coupler including an interlocking three-way valve that enables coupling and uncoupling with respect to a mating nipple only when the coupler is in a vent mode. Preferably, the coupler should be well suited for high pressure applications as a special need exists for a coupler useful in compressed natural gas (CNG) vehicle refueling systems wherein typical service pressures range from 2400 psig (16.5 MPa) to 3600 psig (24.8 MPa). In these systems, the coupler should operate in a manner that minimizes the potential for the escape of the highly pressurized natural gas as well as the potential for misuse. Also, the coupler and mating nipple preferably should be coupled and uncoupled at their front ends at atmospheric pressure even when the back ends of the coupler and/or nipple are under pressure, as would normally be the case in a CNG vehicle refueling system and other fluid pressure systems having a need for a quick-connect, valved fluid coupling with a vent feature.